1. Field of the Invention
This invention relates generally to arrangements for distributing an input force to a plurality of predetermined locations, and more particularly, to an arrangement wherein an input force, such as that which is applied by a windshield wiper arm is distributed to a plurality of locations in predetermining magnitudes along a compliant member, such as a windshield wiper blade.
2. Description of the Related Art
Conventional windshield wiper arrangements employ a plurality of metallic beams pivotally coupled to one another. The respective beams, which generally are not resilient or spring-like, are coupled to a windshield wiper blade at their free ends, and the pivoting of the beams with respect to one another approximates compliant bending of the windshield wiper as it travels across the windshield wiper. One goal to be achieved, however, is to provide a compliant support mechanism that, within predeterminable ranges of displacement of the windshield wiper blade in the direction of the windshield, cause a force to be directed by the windshield wiper blade substantially uniformly along its length onto the surface of the windshield, of a magnitude sufficient to perform the desired windshield wiping function, and for a given windshield contour.
The conventional windshield wiper support arrangement, with its plurality of cantilevered beams, cannot achieve a truly compliant functionality, as it stores within itself little, if any, potential energy. Instead, the arrangement of pivotally attached beams merely approximates a truly compliant mechanism. A further problem with the known arrangements lies in the fact that the cantilevered beams have a limited range of displacement in the direction toward the windshield. A beam cannot be displaced beyond the point where its other end will stop against a sequentially superior beam. The limitation on the amplitude capacity, and hence on the simulated compliance effect, places limitations on vehicle designers, as conventional windshield wiper support systems cannot perform adequately when the windshield surface contour has a relatively small radius of curvature anywhere in the wiping path.
In addition to failing to achieve a compliant function, the known windshield wiper support arrangement is implemented at significant complexity and expense. In most cases, the pivoted beams are made of a metal, that typically is highly reflective of light and subject to corrosion upon exposure to the elements. In order to prevent the glare of the sun on the eyes of the operator of the vehicle, as well as to protect against corrosion, each such pivoted beam must have a non-reflective coating applied thereto. This, of course, is per se a costly step that is rendered more expensive and critical when it is realized that the coating process must be executed with accuracy and precision lest the coating material effect adversely the inter-beam pivot couplings. There are numerous problems that can arise when painted or otherwise coated surfaces move pivotally with respect to one another. If the coating is installed prior to assembly of the product, the coating, at least partially as a result of its thickness, will increase the width of the beams, and decrease the size of the apertures through which the pivots are installed On the other hand, if the product is coated after assembly, the coating process is more complex to avoid leaving areas uncoated, and of course, the coating will tend to accumulate at the pivot joints and at the places where the beams communicate with one another. An overly thick coating causes interference fits and abrasion of the coating, while a coating that is too thin will wear prematurely as a result of exposure to the elements. Clearly, coatings will produce problems irrespective of the point in the manufacture of the product at which they are applied.
There is a need, therefore, for a windshield wiper support arrangement that overcomes the problems described hereinabove, and others.
It is, therefore, an object of this invention to provide a windshield wiper frame arrangement that is simple and inexpensive, and which does not require a complex multi-pivoted interconnection between a windshield wiper actuator arm and the windshield wiper blade.
It is another object of this invention to provide a windshield wiper frame arrangement having precisely controllable compliance characteristics in terms of both, force and deflection.
It is also an object of this invention to provide a windshield wiper frame arrangement that avoids the need for mechanical links and joints.
It is a further object of this invention to provide a windshield wiper frame arrangement that can simply and inexpensively be manufactured as an integral unit, and that does not require subsequent painting.
It is additionally an object of this invention to provide a windshield wiper frame arrangement that can be manufactured in a wide variety of aesthetically pleasing configurations, while retaining high compliance and strength characteristics.
It is yet a further object of this invention to provide a windshield wiper frame arrangement that has a compliance capacity that can easily and inexpensively be made to achieve a specific compliance characteristic for a windshield having a predetermined surface contour, or a group of windshields having a predetermined range of surface contours.